1. Field of the Invention
This invention relates to a rubber pad for an iron crawler belt and a lock pin, which is used therewith, of a caterpillar.
2. Description of the Related Art
In building and engineering machines and the like, which are required for running, an iron crawler belt as a running means has been used. In the iron crawler belt, rectangular iron plates called as xe2x80x9cshoe platesxe2x80x9d pivot with respect to each other so as to form a continuous belt by means of a link mechanism called a xe2x80x9ctrack linkxe2x80x9d and the iron crawler belt is provided. The rubber pads are used with the iron crawler belt for the purpose of hindering from sliding, preventing noise and so on, the rubber pads comprising a single synthetic rubber such as natural rubber, styrene-butadiene rubber, nitrile rubber and the like or a mixture thereof. By the provision of rubber pads having a single or multiple layers of a rubber in the direction of thickness, the impact due to the machine weight is absorbed by the elastic deformation of the rubber and the weight is extremely and uniformly dispersed in running on a paved road surface so that it is intended to prevent the damage of the road surface.
The following caterpillars in the prior art have been developed:
(1) Holes for fitting a rubber pad is formed previously on a shoe plate, and the rubber pad, which rubber is vulcanized and adhered to a metal core, as well as the shoe plate, is tied by means of nuts to the rubber pad with the metal core, to which bolts are welded. (Utility Model Publication No. 63 (1988)-12066; xe2x80x9cRubber Pad for Iron Crawlerxe2x80x9d)
(2) Metal members of a rubber pad, in which rubber is vulcanized and adhered to the members, and a shoe plate is clipped at its ends. (Utility Model Laid-Open No. 63 (1988)-202584; xe2x80x9cStructure for Fitting Rubber Pad in Crawler Running Apparatusxe2x80x9d)
(3) An engaging member, which is united with or separated from the metal core of a rubber pad, a rubber is vulcanized and adhered to the metal core, and a shoe plate is tied with the rubber pad by means of bolts at its ends. (Utility Model Laid-Open No. 56 (1981)-136868; xe2x80x9cPad for Caterpillarxe2x80x9d)
(4) A semicircular groove is formed on opposed surface between a grouser of a shoe plate and a rubber pad and a pair of long pins are inserted into the groove to fit them (Utility Model Laid-Open No. 2 (1965)-42884; xe2x80x9cRubber Pad for Caterpillar Carxe2x80x9d).
In the prior art (1) and (3), however, skill is required to tie a bolt and a nut in a narrow portion of a caterpillar, and it takes a long time to fit and exchange them and the operation is troublesome. In the prior art (2), the shoe plate and the metal member of the rubber pad are fixed by means of clips, so that the clips are apt to fall out through a vibration in running of an engineering mechanism etc. In the prior art (4), a skill for inserting a pair of long pins is required and the pins are apt to fall out because the pins are merely put into rubber against an elastic pressure.
In the prior art as mentioned above, a rubber pad is fixed to a shoe plate by means of a bolt, so that skill is required for tying the bolt. The operation is troublesome, a long time is required for fitting and exchanging them and the work must be performed by an expert, such as a maker or a dealer, disadvantageously. Thus, it is necessary to provide such an iron crawler belt and a rubber pad that may be easily fixed and exchanged and everyone may fit and exchange them on the spot.
In view of the above-mentioned actual circumstances, an object of this invention is to provide a rubber pad for an iron crawler belt and a lock pin, which is used therewith, through which the operation of fitting and exchanging may be performed easily without a bolt.
The invention is a rubber pad to be equipped to an iron crawler belt characterized in that a vulcanized rubber is adhered to a second surface of a flat metal core, first and second bent hooks are respectively provided at both ends of first surface of said metal core, the length of the second hook being greater than that of the first one, and the length of a concavity formed on the first surface of the metal core opposed to the second hook is equal to one fifth of the length of the metal core or less in the direction perpendicular to the traveling direction of the iron crawler belt (in the cross direction of the iron crawler belt). The invention is also characterized in that the ends of a shoe plate of an iron crawler belt can be engaged with and removed from the hooks united with the metal core in the inclined state so that the rubber pad may be simply equipped to the shoe plate without a deformation of the metal core.
The invention also is a rubber pad for an iron crawler belt characterized in that through holes are formed in the metal core and the rubber material protrudes through said through holes to the first surface of the metal core. The invention is also characterized in that the rubber material stands between the metal core and the shoe plate so that metals may not directly contact each other, preventing the abrasion of the metal core and the shoe plate as well as the occurrence of noise.
The invention also is characterized in that another group of through holes are formed approximately at the center of the rubber material, thereby, the mud entering in between the metal core and the shoe plate may be easily discharged outward.
The invention also is directed to a lock pin for fixing the rubber pad for an iron crawler belt to a shoe plate. The invention is characterized in that metal plates are provided on both sides of the lock pin, engaging members in the form of projections are formed at both ends of the metal plates by extending a portion of the metal plates straight in the same direction, an elastic material is adhered between the metal plates on both sides, and the lock pin is formed so as to adapt to the space that is defined with the second hook, the metal core, and the end of the shoe plate. Even when the lengths of the shoe plates have a deviation, an error in the lengths of the shoe plates is counterbalanced due to the flexibility of the elastic material used in the lock pin, which is inserted in the space between the end of the shoe plate and the concavity formed on the metal core, thereby the rubber pad for the iron plate can be fixed closely to the shoe plate.
The invention also is a lock pin for fixing the rubber pad for an iron crawler belt characterized in that at least one surface of each metal plate is inclined so that the lock pin can be easily inserted in the space between the end of a shoe plate and the concavity on the metal core.
The invention also is a lock pin for fixing the rubber pad for an iron crawler belt characterized in that a part of the elastic material projects from the surface, on which the engaging projections of both side metal plates are formed, and the opposed surface thereto. Thereby, the elastic material in the lock pin is pressed on both the shoe plate and the metal core to prevent the falling-out of the lock pin.
The embodiments according to this invention will be illustrated with reference to the drawings hereinafter.